Natural number
There are three types of natural numbers because they can be derived of the numbers 1, 2 and 3.
Explanation
Except for 0, all natural numbers can be derived.
3 → 6 9 12 15 18 21 24 24 30 33 36 39 42 45 ... 2 → 4 8 10 14 16 20 22 26 28 32 34 38 40 44 ... 1 → 5 7 11 13 17 19 23 25 29 31 35 37 41 43 ...
In the bottom row only contains odd numbers. This includes all prime numbers except 2 and 3. In addition to this it contains, the multiples of 5 that are not divisible by 3. This row is used in the investigation of squares of primes.